Piston



' NovQll, 1924. 1,515,543

' G. BOWMAR PISTON Filed Dec. 26, 1922 INVENTOR g I GBOWMAR. F

1 A'rToRNiYs construction 0 Patented Nov. 11, 1924.

may concern:

Be it known that I, GERSHON Bowman a subject of the King of GreatBritain, residing at Toronto, in the county of York, in the Province ofOntario, Canada, have invented certain new and useful Improvements inPistons; and the object of the invention is to devise means to preventthe heat generated by the explosion of gases within the cylinder frompassing through the head and carbonizing the oil therearound, which willnot be aflectedby the heat of the surrounding body of metal to render itinoperative; and it consists, essentially, of a piston head and inclosedair chamber cast within the head in proximity to its upper face and aninterlinin of nonconductin material formed in t e upper wall of t echamber, as hereinaftermore particularly explained by the followingspecification.

Fig. 1 represents a sectional view of my piston head with my air chamberlocated therein.

Fig. 2 is a chamber.

Fig. 3 is a sectional detail of the upper portion of the iston showingan alternative F my device inserted therein.

In the drawings like characters of reference indicate correspondingparts in each figure.

1 indicates a perspective detail of my air piston head of ordinaryconstruction, 2 is a chamber which is formed of sheet metal and castwithin the head against the upper wall 3 thereof so that an annular suporting shoulder is formed at at enga in t e exterior edge of the bottomwall 0 t e chamber. 5 is my heat nonconducting chamber which consists ofan up er outer wall 6 and an upper inner wall 7 ormed of sheet metalwhich are preferably welded together at 8 to form an integral top memberfor the chamber, an intervening space therebetween constituting asecondary chamber provided with a suitable filling 9 of heatnon-conductin material such as fibrous asbestos. 10 is the bottom wallof the chamber which is welded around the outer edge of the outer wall6. The chamber 5 is filled with air.

Heretofore the means devised for-forming a heat non-conducting barrieracross the head of the piston have been in the form of a vacuum chamber.When these chambers were inserted in the mould and the molten I Ya'pumutn mamas, a, mi. am at. am." To all whom it metal poured formingthe pistons the heat of such metal caused the upper wall of the chamberto sag downward as indicated roughly by dotted lines in Fig. 1 therebydestroying the non-conducting effect of the chamber and increasing theweight of the piston.

By my device the air within the chamber serves to some extent to form asupport for the upper wall of thechamber when sub-- ect to the heat ofthe molten meta-l or to eat otherwise enerated, such being aided by thenon-con ucting interlining 9 hereinbefore described thereby formin achamber top which will always be rigi and have no tendency to sagdownward and therefore always form a perfect chamber forming apractically perfect barrier to any heat radiating downward through thepiston.

In the construction shown in Fig. 3 the bottom wall is dispensed with,the double wall construction forming an open chamber, the interveningspace between the double wall being filled with asbestos or forming adead air space.

By my construction also the piston may be made more compact, that is,with. the wrist pin located nearer to the head than is permissible inthe ordinary construction for the reason that the wrist pin in myconstruction will not be effected by the heat passing through the pistonhead when in close. proximity to the head as is the case in the ordinaryconstruction of piston head.

What I claim as my invention is:

1. In a piston, a ,piston body, an air chamber secured entirely withinsaid body and having spaced secondar chamber, and a filling of heatnon-con ucting material for said secondary chamber.

2. In apiston, a body interior, a reinfoncin member in double wallformation rigi y supported within said body in engagement wlth theinterior face of the piston head and having a filling of heatnon-conducting material, and an air chamber closing in said reinforcingmember.

. ,3. The combination in a air chamber formed of non-porous metalpositioned therewithin, of a secondary chamber positioned between saidair chamber and the iston head, and a filling of heat non-con uctingmaterial for said secondary chamber.

piston having an having a hollow upper walls forming a 4. In a pistonhead, eheat non-eomlncti1' barrier censisting of a 'ca likemember non'porousmetal loca within the forward end of the piston and eomprism up-.5 per and lower and intermediate wells ermingdpetallel chambers, and

con ucting material between intermediate walls.

a filling of nonsaid upper and piston and com metal wall having-theirouter 5." In 9. piston head,

afilling of material between such wells.

GERSHON BOWMAB.

turned and drawn together, and non-eonducting e ca -l1'ke' memberend ofthe

